Genetic and Cellular Characterization of Caenorhabditis elegans Mutants Abnormal in the Regulation of Many Phase II Enzymes
نویسندگان
چکیده
BACKGROUND The phase II detoxification enzymes execute a major protective role against xenobiotics as well as endogenous toxicants. To understand how xenobiotics regulate phase II enzyme expression, acrylamide was selected as a model xenobiotic chemical, as it induces a large number and a variety of phase II enzymes, including numerous glutathione S-transferases (GSTs) in Caenorhabditis elegans. METHODOLOGY/PRINCIPAL FINDINGS To begin dissecting genetically xenobiotics response pathways (xrep), 24 independent mutants of C. elegans that exhibited abnormal GST expression or regulation against acrylamide were isolated by screening about 3.5x10(5) genomes of gst::gfp transgenic strains mutagenized with ethyl methanesulfonate (EMS). Complementation testing assigned the mutants to four different genes, named xrep-1, -2, -3, and -4. One of the genes, xrep-1, encodes WDR-23, a nematode homologue of WD repeat-containing protein WDR23. Loss-of-function mutations in xrep-1 mutants resulted in constitutive expression of many GSTs and other phase II enzymes in the absence of acrylamide, and the wild-type xrep-1 allele carried on a DNA construct successfully cured the mutant phenotype of the constitutive enzyme expression. CONCLUSIONS/SIGNIFICANCE Genetic and cellular characterization of xrep-1 mutants suggest that a large number of GSTs and other phase II enzymes induced by acrylamide are under negative regulation by XREP-1 (WDR-23), which is likely to be a functional equivalent of mammalian Keap1 and a regulator of SKN-1, a C. elegans analogue of cap-n-collar Nrf2 (nuclear factor erythroid 2-related factor 2).
منابع مشابه
ویژگیهای بیوشیمیایی گیاهان آرابیدوپسیس جهشیافته ntrc طی پیری القاء شده توسط تاریکی
Abstract Thioredoxins are invoved in redox regulation of many cellular processes. In this study the role of NADP+-Thioredoxin reductase C (NTRC) in the control of leaf senescence was investigated by biochemical characterization of Arabidopsis ntrc mutants. Forty days old wild type and two ntrc mutant lines were incubated either under normal dark-light or continous darkness regimes for 6 days as...
متن کاملA Genetic Screen for Mutants with Supersized Lipid Droplets in Caenorhabditis elegans
To identify genes that regulate the dynamics of lipid droplet (LD) size, we have used the genetically tractable model organism Caenorhabditis elegans, whose wild-type LD population displays a steady state of size with an upper limit of 3 μm in diameter. From a saturated forward genetic screen of 6.7 × 10(5) mutagenized haploid genomes, we isolated 118 mutants with supersized intestinal LDs ofte...
متن کاملDetermination of the effects of food preservatives benzoic acid and sodium nitrate on lifespan, fertility and physical growth in Caenorhabditis elegans
Presently, the use of protective food additives such as benzoic acid and sodium nitrate is quite common. However, it was found that these additives, which initially appeared to be harmless, led to the emergence of a number of health problems. Cancer and diseases and deaths with no apparent causes are among the leading concerns. Therefore, the studies which can reveal the genotoxic potential of ...
متن کاملDAF-16 and Δ9 Desaturase Genes Promote Cold Tolerance in Long-Lived Caenorhabditis elegans age-1 Mutants
In Caenorhabditis elegans, mutants of the conserved insulin/IGF-1 signalling (IIS) pathway are long-lived and stress resistant due to the altered expression of DAF-16 target genes such as those involved in cellular defence and metabolism. The three Δ(9) desaturase genes, fat-5, fat-6 and fat-7, are included amongst these DAF-16 targets, and it is well established that Δ(9) desaturase enzymes pl...
متن کاملFunctional Genomic Analysis of the let-7 Regulatory Network in Caenorhabditis elegans
The let-7 microRNA (miRNA) regulates cellular differentiation across many animal species. Loss of let-7 activity causes abnormal development in Caenorhabditis elegans and unchecked cellular proliferation in human cells, which contributes to tumorigenesis. These defects are due to improper expression of protein-coding genes normally under let-7 regulation. While some direct targets of let-7 have...
متن کامل